Increased expression of the full-length androgen receptor (AR-FL) and AR splice variants (AR-Vs) drives the progression of castration-resistant prostate cancer (CRPC). The levels of AR-FL and AR-V transcripts are often tightly correlated in individual CRPC samples, yet our understanding of how their expression is co-regulated is limited. Here, we report a role of c-Myc in accounting for coordinated AR-FL and AR-V expression. Analysis of gene-expression data from 159 metastatic CRPC samples and 2142 primary prostate tumors showed that the level of c-Myc is positively correlated with that of individual AR isoforms. A striking positive correlation also exists between the activity of the c-Myc pathway and the level of individual AR isoforms, between the level of c-Myc and the activity of the AR pathway, and between the activities of the two pathways. Moreover, the c-Myc signature is highly enriched in tumors expressing high levels of AR, as is the AR signature in c-Myc-high-expressing tumors. Using shRNA knockdown, we confirmed c-Myc regulation of expression and activity of AR-FL and AR-Vs in cell models and a patient-derived xenograft model. Mechanistically, c-Myc promotes the transcription of the AR gene and enhances the stability of the AR-FL and AR-V proteins without altering AR RNA splicing. Importantly, inhibiting c-Myc sensitizes enzalutamide-resistant cells to growth inhibition by enzalutamide. Overall, this study highlights a critical role of c-Myc in regulating the coordinated expression of AR-FL and AR-Vs that is commonly observed in CRPC and suggests the utility of targeting c-Myc as an adjuvant to AR-directed therapy.
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Knudsen KE, Scher HI. Starving the addiction: new opportunities for durable suppression of AR signaling in prostate cancer. Clin Cancer Res. 2009;15:4792–8.
Nuhn P, De Bono JS, Fizazi K, Freedland SJ, Grilli M, Kantoff PW, et al. Update on systemic prostate cancer therapies: management of metastatic castration-resistant prostate cancer in the era of precision oncology. Eur Urol. 2019;75:88–99.
Smith MR, Saad F, Chowdhury S, Oudard S, Hadaschik BA, Graff JN, et al. Apalutamide treatment and metastasis-free survival in prostate cancer. N Engl J Med. 2018;378:1408–18.
Scher HI, Fizazi K, Saad F, Taplin ME, Sternberg CN, Miller K, et al. Increased survival with enzalutamide in prostate cancer after chemotherapy. N Engl J Med. 2012;367:1187–97.
de Bono JS, Logothetis CJ, Molina A, Fizazi K, North S, Chu L, et al. Abiraterone and increased survival in metastatic prostate cancer. N Engl J Med. 2011;364:1995–2005.
Antonarakis ES, Lu C, Wang H, Luber B, Nakazawa M, Roeser JC, et al. AR-V7 and resistance to enzalutamide and abiraterone in prostate cancer. N Engl J Med. 2014;371:1028–38.
Cao B, Qi Y, Zhang G, Xu D, Zhan Y, Alvarez X, et al. Androgen receptor splice variants activating the full-length receptor in mediating resistance to androgen-directed therapy. Oncotarget. 2014;5:1646–56. 1802 pii.
Li Y, Chan SC, Brand LJ, Hwang TH, Silverstein KA, Dehm SM. Androgen receptor splice variants mediate enzalutamide resistance in castration-resistant prostate cancer cell lines. Cancer Res. 2013;73:483–9.
Mostaghel EA, Marck BT, Plymate SR, Vessella RL, Balk S, Matsumoto AM, et al. Resistance to CYP17A1 inhibition with abiraterone in castration-resistant prostate cancer: induction of steroidogenesis and androgen receptor splice variants. Clin Cancer Res. 2011;17:5913–25.
Nadiminty N, Tummala R, Liu C, Yang J, Lou W, Evans CP, et al. NF-kappaB2/p52 induces resistance to enzalutamide in prostate cancer: role of androgen receptor and its variants. Mol Cancer Ther. 2013;12:1629–37.
Cao S, Zhan Y, Dong Y. Emerging data on androgen receptor splice variants in prostate cancer. Endocr Relat Cancer. 2016;23:T199–T210.
Chan SC, Li Y, Dehm SM. Androgen receptor splice variants activate androgen receptor target genes and support aberrant prostate cancer cell growth independent of canonical androgen receptor nuclear localization signal. J Biol Chem. 2012;287:19736–49.
Dehm SM, Schmidt LJ, Heemers HV, Vessella RL, Tindall DJ. Splicing of a novel androgen receptor exon generates a constitutively active androgen receptor that mediates prostate cancer therapy resistance. Cancer Res. 2008;68:5469–77.
Guo Z, Yang X, Sun F, Jiang R, Linn DE, Chen H, et al. A novel androgen receptor splice variant is up-regulated during prostate cancer progression and promotes androgen depletion-resistant growth. Cancer Res. 2009;69:2305–13.
Hu R, Dunn TA, Wei S, Isharwal S, Veltri RW, Humphreys E, et al. Ligand-independent androgen receptor variants derived from splicing of cryptic exons signify hormone-refractory prostate cancer. Cancer Res. 2009;69:16–22.
Hu R, Isaacs WB, Luo J. A snapshot of the expression signature of androgen receptor splicing variants and their distinctive transcriptional activities. Prostate. 2011;71:1656–67.
Sun S, Sprenger CC, Vessella RL, Haugk K, Soriano K, Mostaghel EA, et al. Castration resistance in human prostate cancer is conferred by a frequently occurring androgen receptor splice variant. J Clin Invest. 2010;120:2715–30.
Watson PA, Chen YF, Balbas MD, Wongvipat J, Socci ND, Viale A, et al. Constitutively active androgen receptor splice variants expressed in castration-resistant prostate cancer require full-length androgen receptor. Proc Natl Acad Sci USA. 2010;107:16759–65.
Hornberg E, Ylitalo EB, Crnalic S, Antti H, Stattin P, Widmark A, et al. Expression of androgen receptor splice variants in prostate cancer bone metastases is associated with castration-resistance and short survival. PLoS ONE. 2011;6:e19059.
Scher HI, Lu D, Schreiber NA, Louw J, Graf RP, Vargas HA, et al. Association of AR-V7 on circulating tumor cells as a treatment-specific biomarker with outcomes and survival in castration-resistant prostate cancer. JAMA Oncol. 2016;2:1441–9.
Welti J, Rodrigues DN, Sharp A, Sun S, Lorente D, Riisnaes R, et al. Analytical validation and clinical qualification of a new immunohistochemical assay for androgen receptor splice variant-7 protein expression in metastatic castration-resistant prostate cancer. Eur Urol. 2016;70:599–608.
Todenhofer T, Azad A, Stewart C, Gao J, Eigl BJ, Gleave ME, et al. AR-V7 transcripts in whole blood RNA of patients with metastatic castration resistant prostate cancer correlate with response to abiraterone acetate. J Urol. 2017;197:135–42.
Li Y, Alsagabi M, Fan D, Bova GS, Tewfik AH, Dehm SM. Intragenic rearrangement and altered RNA splicing of the androgen receptor in a cell-based model of prostate cancer progression. Cancer Res. 2011;71:2108–17.
Nyquist MD, Li Y, Hwang TH, Manlove LS, Vessella RL, Silverstein KA, et al. TALEN-engineered AR gene rearrangements reveal endocrine uncoupling of androgen receptor in prostate cancer. Proc Natl Acad Sci USA. 2013;110:17492–7.
Miyamoto DT, Zheng Y, Wittner BS, Lee RJ, Zhu H, Broderick KT, et al. RNA-Seq of single prostate CTCs implicates noncanonical Wnt signaling in antiandrogen resistance. Science. 2015;349:1351–6.
Liu LL, Xie N, Sun S, Plymate S, Mostaghel E, Dong X. Mechanisms of the androgen receptor splicing in prostate cancer cells. Oncogene. 2014;33:3140–50.
Zhang Z, Zhou N, Huang J, Ho TT, Zhu Z, Qiu Z, et al. Regulation of androgen receptor splice variant AR3 by PCGEM1. Oncotarget. 2016;7:15481–91.
Nadiminty N, Tummala R, Liu C, Lou W, Evans CP, Gao AC. NF-kappaB2/p52:c-Myc:hnRNPA1 pathway regulates expression of androgen receptor splice variants and enzalutamide sensitivity in prostate cancer. Mol Cancer Ther. 2015;14:1884–95.
Tummala R, Nadiminty N, Lou W, Evans CP, Gao AC. Lin28 induces resistance to anti-androgens via promotion of AR splice variant generation. Prostate. 2016;76:445–55.
Fan L, Zhang F, Xu S, Cui X, Hussain A, Fazli L, et al. Histone demethylase JMJD1A promotes alternative splicing of AR variant 7 (AR-V7) in prostate cancer cells. Proc Natl Acad Sci USA. 2018;115:E4584–93.
Stockley J, Markert E, Zhou Y, Robson CN, Elliott DJ, Lindberg J, et al. The RNA-binding protein Sam68 regulates expression and transcription function of the androgen receptor splice variant AR-V7. Sci Rep. 2015;5:13426.
Shiota M, Fujimoto N, Imada K, Yokomizo A, Itsumi M, Takeuchi A et al. Potential role for YB-1 in castration-resistant prostate cancer and resistance to enzalutamide through the androgen receptor V7. J Natl Cancer Inst 2016;108:djw005.
Ferraldeschi R, Welti J, Powers MV, Yuan W, Smyth T, Seed G. et al. Second-generation HSP90 inhibitor onalespib blocks mRNA splicing of androgen receptor variant 7 in prostate cancer cells. Cancer Res. 2016;76:2731–42.
Yu Z, Chen S, Sowalsky AG, Voznesensky OS, Mostaghel EA, Nelson PS, et al. Rapid induction of androgen receptor splice variants by androgen deprivation in prostate cancer. Clin Cancer Res. 2014;20:1590–1600.
Sharp A, Coleman I, Yuan W, Sprenger C, Dolling D, Nava Rodrigues D, et al. Androgen receptor splice variant-7 expression emerges with castration resistance in prostate cancer. J Clin Invest 2018;129:192–208.
Tomlins SA, Mehra R, Rhodes DR, Cao X, Wang L, Dhanasekaran SM, et al. Integrative molecular concept modeling of prostate cancer progression. Nat Genet. 2007;39:41–51.
Koh CM, Bieberich CJ, Dang CV, Nelson WG, Yegnasubramanian S, De Marzo AM. MYC and prostate cancer. Genes Cancer. 2010;1:617–28.
Grad JM, Dai JL, Wu S, Burnstein KL. Multiple androgen response elements and a Myc consensus site in the androgen receptor (AR) coding region are involved in androgen-mediated up-regulation of AR messenger RNA. Mol Endocrinol. 1999;13:1896–911.
Nadiminty N, Tummala R, Lou W, Zhu Y, Zhang J, Chen X, et al. MicroRNA let-7c suppresses androgen receptor expression and activity via regulation of Myc expression in prostate cancer cells. J Biol Chem. 2012;287:1527–37.
Gao L, Schwartzman J, Gibbs A, Lisac R, Kleinschmidt R, Wilmot B, et al. Androgen receptor promotes ligand-independent prostate cancer progression through c-Myc upregulation. PLoS ONE. 2013;8:e63563.
Robinson D, Van Allen EM, Wu YM, Schultz N, Lonigro RJ, Mosquera JM, et al. Integrative clinical genomics of advanced prostate cancer. Cell. 2015;161:1215–28.
Wang L, Dehm SM, Hillman DW, Sicotte H, Tan W, Gormley M, et al. A prospective genome-wide study of prostate cancer metastases reveals association of wnt pathway activation and increased cell cycle proliferation with primary resistance to abiraterone acetate-prednisone. Ann Oncol. 2018;29:352–60.
Beltran H, Prandi D, Mosquera JM, Benelli M, Puca L, Cyrta J, et al. Divergent clonal evolution of castration-resistant neuroendocrine prostate cancer. Nat Med. 2016;22:298–305.
Schuhmacher M, Kohlhuber F, Holzel M, Kaiser C, Burtscher H, Jarsch M, et al. The transcriptional program of a human B cell line in response to Myc. Nucleic Acids Res. 2001;29:397–406.
Jung M, Russell AJ, Liu B, George J, Liu PY, Liu T, et al. A Myc activity signature predicts poor clinical outcomes in Myc-associated cancers. Cancer Res. 2017;77:971–81.
Erho N, Crisan A, Vergara IA, Mitra AP, Ghadessi M, Buerki C, et al. Discovery and validation of a prostate cancer genomic classifier that predicts early metastasis following radical prostatectomy. PLoS ONE. 2013;8:e66855.
Nakagawa T, Kollmeyer TM, Morlan BW, Anderson SK, Bergstralh EJ, Davis BJ, et al. A tissue biomarker panel predicting systemic progression after PSA recurrence post-definitive prostate cancer therapy. PLoS ONE. 2008;3:e2318.
Karnes RJ, Bergstralh EJ, Davicioni E, Ghadessi M, Buerki C, Mitra AP, et al. Validation of a genomic classifier that predicts metastasis following radical prostatectomy in an at risk patient population. J Urol. 2013;190:2047–53.
Klein EA, Yousefi K, Haddad Z, Choeurng V, Buerki C, Stephenson AJ, et al. A genomic classifier improves prediction of metastatic disease within 5 years after surgery in node-negative high-risk prostate cancer patients managed by radical prostatectomy without adjuvant therapy. Eur Urol. 2015;67:778–86.
Prensner JR, Zhao S, Erho N, Schipper M, Iyer MK, Dhanasekaran SM, et al. RNA biomarkers associated with metastatic progression in prostate cancer: a multi-institutional high-throughput analysis of SChLAP1. Lancet Oncol. 2014;15:1469–80.
Den RB, Feng FY, Showalter TN, Mishra MV, Trabulsi EJ, Lallas CD, et al. Genomic prostate cancer classifier predicts biochemical failure and metastases in patients after postoperative radiation therapy. Int J Radiat Oncol Biol Phys. 2014;89:1038–46.
Freedland SJ, Choeurng V, Howard L, De Hoedt A, du Plessis M, Yousefi K, et al. Utilization of a genomic classifier for prediction of metastasis following salvage radiation therapy after radical prostatectomy. Eur Urol. 2016;70:588–96.
Ross AE, Johnson MH, Yousefi K, Davicioni E, Netto GJ, Marchionni L, et al. Tissue-based genomics augments post-prostatectomy risk stratification in a natural history cohort of intermediate- and high-risk men. Eur Urol. 2016;69:157–65.
Corey E, Quinn JE, Buhler KR, Nelson PS, Macoska JA, True LD, et al. LuCaP 35: a new model of prostate cancer progression to androgen independence. Prostate. 2003;55:239–46.
Burnstein KL. Regulation of androgen receptor levels: implications for prostate cancer progression and therapy. J Cell Biochem. 2005;95:657–69.
Hu R, Lu C, Mostaghel EA, Yegnasubramanian S, Gurel M, Tannahill C, et al. Distinct transcriptional programs mediated by the ligand-dependent full-length androgen receptor and its splice variants in castration-resistant prostate cancer. Cancer Res. 2012;72:3457–62.
Chen Z, Wu D, Thomas-Ahner JM, Lu C, Zhao P, Zhang Q, et al. Diverse AR-V7 cistromes in castration-resistant prostate cancer are governed by HoxB13. Proc Natl Acad Sci USA. 2018;115:6810–5.
Nelson PS, Clegg N, Arnold H, Ferguson C, Bonham M, White J, et al. The program of androgen-responsive genes in neoplastic prostate epithelium. Proc Natl Acad Sci USA. 2002;99:11890–5.
Bluemn EG, Coleman IM, Lucas JM, Coleman RT, Hernandez-Lopez S, Tharakan R, et al. Androgen receptor pathway-independent prostate cancer is sustained through FGF signaling. Cancer Cell. 2017;32:474–89 e476.
Yin X, Giap C, Lazo JS, Prochownik EV. Low molecular weight inhibitors of Myc–Max interaction and function. Oncogene. 2003;22:6151–9.
Cao B, Qi Y, Yang Y, Liu X, Xu D, Guo W, et al. 20(S)-protopanaxadiol inhibition of progression and growth of castration-resistant prostate cancer. PLoS ONE. 2014;9:e111201.
Kregel S, Chen JL, Tom W, Krishnan V, Kach J, Brechka H, et al. Acquired resistance to the second-generation androgen receptor antagonist enzalutamide in castration-resistant prostate cancer. Oncotarget. 2016;7:26259–74.
Barfeld SJ, Urbanucci A, Itkonen HM, Fazli L, Hicks JL, Thiede B, et al. c-Myc antagonises the transcriptional activity of the androgen receptor in prostate cancer affecting key gene networks. EBioMedicine. 2017;18:83–93.
Nag A, Smith RG. Amplification, rearrangement, and elevated expression of c-myc in the human prostatic carcinoma cell line LNCaP. Prostate. 1989;15:115–22.
Chen CH, Zhang J, Ling CC. Transfected c-myc and c-Ha-ras modulate radiation-induced apoptosis in rat embryo cells. Radiat Res. 1994;139:307–15.
Askew DS, Ashmun RA, Simmons BC, Cleveland JL. Constitutive c-myc expression in an IL-3-dependent myeloid cell line suppresses cell cycle arrest and accelerates apoptosis. Oncogene. 1991;6:1915–22.
Guo J, Parise RA, Joseph E, Egorin MJ, Lazo JS, Prochownik EV, et al. Efficacy, pharmacokinetics, tisssue distribution, and metabolism of the Myc-Max disruptor, 10058-F4 [Z,E]−5-[4-ethylbenzylidine]-2-thioxothiazolidin-4-one, in mice. Cancer Chemother Pharmacol. 2009;63:615–25.
Whitfield JR, Beaulieu ME, Soucek L. Strategies to inhibit Myc and their clinical applicability. Front Cell Dev Biol. 2017;5:10.
Carabet LA, Lallous N, Leblanc E, Ban F, Morin H, Lawn S, et al. Computer-aided drug discovery of Myc-Max inhibitors as potential therapeutics for prostate cancer. Eur J Med Chem. 2018;160:108–19.
Piccolo SR, Sun Y, Campbell JD, Lenburg ME, Bild AH, Johnson WE. A single-sample microarray normalization method to facilitate personalized-medicine workflows. Genomics. 2012;100:337–44.
Zhao SG, Chang SL, Erho N, Yu M, Lehrer J, Alshalalfa M, et al. Associations of luminal and basal subtyping of prostate cancer with prognosis and response to androgen deprivation therapy. JAMA Oncol. 2017;3:1663–72.
Li B, Dewey CN. RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome. BMC Bioinforma. 2011;12:323.
Ungerleider N, Concha M, Lin Z, Roberts C, Wang X, Cao S, et al. The Epstein Barr virus circRNAome. PLoS Pathog. 2018;14:e1007206.
Dong Y, Zhang H, Hawthorn L, Ganther HE, Ip C. Delineation of the molecular basis for selenium-induced growth arrest in human prostate cancer cells by oligonucleotide array. Cancer Res. 2003;63:52–59.
Dong Y, Lee SO, Zhang H, Marshall J, Gao AC, Ip C. Prostate specific antigen expression is down-regulated by selenium through disruption of androgen receptor signaling. Cancer Res. 2004;64:19–22.
Vichai V, Kirtikara K. Sulforhodamine B colorimetric assay for cytotoxicity screening. Nat Protoc. 2006;1:1112–6.
Stewart SA, Dykxhoorn DM, Palliser D, Mizuno H, Yu EY, An DS, et al. Lentivirus-delivered stable gene silencing by RNAi in primary cells. RNA. 2003;9:493–501.
Pang S, Dannull J, Kaboo R, Xie Y, Tso CL, Michel K, et al. Identification of a positive regulatory element responsible for tissue-specific expression of prostate-specific antigen. Cancer Res. 1997;57:495–9.
Xu D, Zhan Y, Qi Y, Cao B, Bai S, Xu W, et al. Androgen receptor splice variants dimerize to transactivate target genes. Cancer Res. 2015;75:3663–71.
Cao B, Liu X, Li J, Liu S, Qi Y, Xiong Z, et al. 20(S)-protopanaxadiol-aglycone downregulation of the full-length and splice variants of androgen receptor. Int J Cancer. 2013;132:1277–87.
Sears R, Ohtani K, Nevins JR. Identification of positively and negatively acting elements regulating expression of the E2F2 gene in response to cell growth signals. Mol Cell Biol. 1997;17:5227–35.
Younis I, Berg M, Kaida D, Dittmar K, Wang C, Dreyfuss G. Rapid-response splicing reporter screens identify differential regulators of constitutive and alternative splicing. Mol Cell Biol. 2010;30:1718–28.
Dong Y, Zhang H, Gao AC, Marshall JR, Ip C. Androgen receptor signaling intensity is a key factor in determining the sensitivity of prostate cancer cells to selenium inhibition of growth and cancer-specific biomarkers. Mol Cancer Ther. 2005;4:1047–55.
We are grateful to Dr. Alan Meeker at Johns Hopkins University for providing LNCaP95 cells, to Dr. Donald Vander Griend at the University of Illinois at Chicago for providing CWR-R1-EnzR cells, and to Dr. Robert Matusik at Vanderbilt School of Medicine for providing the ARR3-luc construct. We appreciate the support from the Tulane Cancer Next Generation Sequence Analysis core for utilization of resources and expertise for this work.
Conflict of interest
This work was supported by the following grants: the National Institutes of Health grants R01CA188609, R01AI101046, R01AI106676, P01CA214091, RCMI 2G12MD007595, and P20GM103518; Department of Defense grants W81XWH-15-1-0439, W81XWH-16-1-0317, W81XWH-16-1-0318, and W81XWH-14-1-0485; National Natural Science Foundation of China Project 81430087. The Richard M. Lucas Foundation supported the development of the LuCaP 35CR model. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.
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International Journal of Molecular Sciences (2019)
Expert Opinion on Therapeutic Patents (2019)